Update UI

[wpalani]

Proposed changes

Initially, I wanted to address this internal ticket PRESS1-388, but then I noticed a few things to improve, including design and accessibility, so I decided to address them all in this PR.

• Tweak the design of the content, bringing it closer to WordPress styles to make it feel more native.
• Improve mobile styles.
• Add the step number to the modal at the bottom right corner of the modal's content.
• Remove deactivation duration experiment (per @chrisdavidmiles)
• Fix an issue where the ESC key doesn't close the modal on the second step.
• Fix an issue where closing the modal on the second step removes the ability to trigger the modal again.
• Make tests more granular.

Demo

ds_ui.mp4

Mobile:

Type of Change

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices apply)

Checklist

• I have read the CONTRIBUTING doc
• Linting and tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments